Method of and apparatus for gas distribution



Oct. 31, 1933. H. D. STRAIGHT 1,932,537

METHOD OF AND APPARATUS FOR GAS DISTRIBUTION Filed Oct. 1. 1929 Patented Oct. 31, 1933 UNITED STATES PATENT. OFFICE METHOD or AND APPARATUS ron GAS- DISTRIBUTION Application October 1, 1929. Serial No. 396,177 9 Claims. (Cl- 48-190) This invention relates to the distribution of gas and more particularly to the lubrication of the interior of the pipes or mains used in such distribution.

5 The interior of the mains used for the distribution of manufactured gas are ordinarily covered with a heavy deposit of rust formed by the corrosive action of the aqueous condensate in combination with traces of certain impurities in the 1 gas such as 02, H2S, I-ICN, etc. If the ordinarily wet gas should be subjected to dehydration before distribution, or should dry natural gas be turned into mains formerly used for the distribution of (wet) manufactured gas the rust deposits 5 dry out and become .dislodged. These rust particles may then be picked up by the gas flowing in the mains and cause considerable annoyance and damage such as stoppage of pilot lights, depositing in regulator's, cutting of meter valves and filling up service pipes.

If, however, a fine oil mist or fog is mixed with the gas the former water-wet conditions of the mains is replaced by an oil-wet one and the rust particles are held in place.

g5 Laboratory tests and practical experience show that it is not possible to lubricate adequately an entire distribution system from one point, but that this lubrication by oil fog must be effected from a number of points throughout the system. Tests still further show that one 01' the preferable means of formation of oil fog of the requisite fineness of particle size is atomization of the oil by means of aspiration with a jet of compressed gas.

The mains of a distribution system are ordinarily accessible for the/insertion of lubrication devices at governor or regulator pits. However, there is ordinarily no high pressure (15 to pounds gauge) gas available at these pits for the atomization of the oil, and the provision of this compressed gas is somewhat of a problem. The particular problem is the provision of suitable motive power to drive a compressor to furnish the gas at the required spraying pressure.

Electrical outlets for motors are not available at governor pits. Their installation is open to the further objection of the explosive hazard involved in operating such a motor in the atmosphere of a governor pit which may, at times, contain gas. The same objection may be made against a small gas or gasoline engine with the further disadvantage that the noise of its exhaust will be objectionable in residential districts.

By my invention I have efiectively overcome the objections which may be raised against the above forms or motive power and have provided a means ideally suited to the purpose. The basic prin-, ciple o! my invention is the utilization of the gas pressure differential existing between the transmission and low pressure mains, governor pits, as a power means.

In the preferred embodiment of my invention I expand the gas trom the tron main through a positive pressure blower into the low pressure mains. This blower is connected to a compressor of any suitable type which provides the compressed gas for the oil spray device.

A practical embodiment of my invention is shown in the accompanying drawing in which:

Figure 1 is an elevational view, partly in crosssection, of the apparatus of the invention as installed in a governor pit;

Fig. 2 is an enlarged vertical sectional view of the atomizer; and

Fig. 3 is a plan viewof the atomizer and cen- 76 tritugal settling chamber.

As shown in Fig. 1, a high pressure or transmission main 1 and a low pressure main 2 have a pressure reducing valve 3 located therebetween and through which the mains are connected. 80 The valve is provided with balanced discs 4, a diaphragm 5 and weight 6. In actual practice such a reducing or governor pit valve is provided with numerous accessories such as auxiliary regulating valves, not herein shown or described.

A branch pipe 7 leads gas from the main 1 on the high pressure side of the reducing valve through an expansion chamber motor 8, herein shown as a positive pressure blower operated as a motor instead of as a pump. The exhaust gas passes through a pipe 9 into the low pressure main 2.

The motor may be of the reciprocating piston type, such as is used for compressed air motors and steam engines, of the bellows type, such as is used in gas meters, or it may be of the turbine yp In this particular embodiment of the invention, the blower 8 has a displacement or 0.12 cu. ft. per revolution and is connected through a chain 11 to a small reciprocating pump 12 which has a capacity of one-halt cu. ft. per minute at 30 pounds. The drive may be direct, it desired, instead of through an endless chain. pipe 13 connected to pipe 7 or to the high pressure side of the reducing valve 3 serves as the inlet for the compressor 12. An outlet pipe 14 leads to a small tank or surge chamber 15 which for example at 60 g absorbs pulsations and the compressed gas then passes through a pipe 16 to an atomizer 17.

The spray from the atomizer 1'7 passes through tangential inlet 18 to a tank 19, the upper part or which serves as a centrifugal settling or whirling chamber. The lower part of the tank 19 serves as a reservoir for the oil which is drawn into the atomizer 17 through a pipe 20.

After the spray is whirled and the large particles of oil fog are settled out the remainder passes from the center of the whirling chamber through pipe 21 to the gas main 2.

Since the pressure differential existing between the high pressure and low pressure sides of the reducing valve varies widely in accordance with the relative rates of production of the gas plant and of gas consumption on the part of the consumers, I have found it desirable to further provide the pressure limiting or regulating valve 23 provided with the usual diaphragm 24 and weight 25 on the high pressure gas line 7 that supplies gas to the motor 8.

The operation of the unit is such that it will start at a pressure diflerential of 15 inches of water at which differential 13 lbs. of pressure is developed in the pipes 14 and 16 leading to the atomizer or spray nozzle 17. The regulating valve 23 is set to limit the pressure difierential across the blower 8, serving as a motor, to 30 inches of Water pressure under which pressure the motor 8 rotates approximately 250 revolutions per minute and 30 lbs. gas pressure is developed by the reciprocating pump 12.

,The use of an oil fog in the gas passing through the mains not only results in the prevention of rust, which loosens and passes along with the gas in the form of dust, but also in several additional advantages. These are: sealing of minute leaks in the main, prevention of the drying out of pipe joints, alleviation of naphthalene troubles, and a beneficial effect on meter leathers.

The present fog producing apparatus, being adapted to be installed in governor pits, can be used in a number of widely scattered points throughout the distribution system for an entire city, so that all of the above enumerated advantages can be had throughout the system, instead of in a very limited area adjacent to the main gas works, as is the case with former devices for placing oil fog in gas mains.

A particular advantage of this unit is that it does not run during periods when little gas is flowing in the mains; since, at these times, the pressure diiferential is below the 15 inches of water required to start the apparatus. Also, the amount of oil fog produced is roughly proportional to the gas flowing in the low pressure mains since at times of maximum flow the pressure differential is greatest and the gas pressures developed by the pump for the spray nozzle is the highest.

Not only is the apparatus free from fire peril, but after installation is out of the way, requires no additional rooms or buildings and does not require the presence of an attendant.

I claim as my invention:

1. In a gas distribution system, a low pressure gas main, a high pressure main for supplying gas to the low pressure main, a motor driven by the pressure of gas from the high pressure main and exhausting into the low pressure main, an atomizer for oil connected to discharge into said low pressure main, and a compressor driven by said motor and utilizing gas from the high pressure main for supplying gas to said atomizer,

meats? 2. In a gas distribution system, a low pressure gas main, a high pressure gas main a motor driven by the passage of gas from the high pressure to the low pressure main, a compressor driven by the motor for compressing gas from the high pressure main, an oil atomizer, means for supplying oil thereto, means for supplying compressed gas from the compressor to the oil atomizer for atomizing oil and means for conducting oil-bearing gas from the atomizer into the low pressure main.

3. In a gas distribution system, conduits for gas at two pressures, a motor actuated by the passage of some of the gas from the high pressure conduit to the low pressure conduit, a compressor actuated by the motor for compressing gas from one of the conduits to high pressure, an oil atomizer connected with the outlets of the compressor for entraining some of the oil in the gas from the compressor, means for supplying oil to the atomizer, and means for conducting the atomized oil-bearing gas from the atomizer to the conduit of lower pressure.

4. In a gas distribution system, a low pressure main, a high pressure main for supplying gas to said low pressure main, an oil atomizer, means for supplying oil thereto, a compressor adapted for compressing a limited volume of gas from one of said mains and for supplying the compressed gas to the oil atomizer for atomizing the oil therein, a motor for driving the compressor, means for driving said motor comprising a gas expansion chamber adapted to drive the motor upon expansion of gas under pressure, inlet and exhaust connections for supplying gas from the high pressure main to said means to drive the motor and for exhausting the driving gas into the low pressure main, and means for conducting the atomized oil from the atomizer into the low pressure main.

5. In a gas distribution system, a low pressure main, a high pressure main for supplying gas to said low pressure main, an oil atomizer, means for supplying oil thereto, a compressor adapted for compressing a limited volume of gas from the high pressure main and for supplying the compressed gas to the oil atomizer for atomizing the oil therein, a motor for driving the compressor, means for driving said motor comprising a gas expansion chamber adapted to drive the motor upon expansion of gas under pressure, inlet and exhaust connections for supplying gas from the high pressure main to said means to drive the motor for exhausting the driving gas into the low pressure main, and means for conducting the atomized oil from the atomizer into the low pressure main.

6. In a gas distribution system the combination with a high pressure gas main and a low pressure gas main, of an oil atomizer connected to discharge atomized oil into said low pressure gas main, and compressing means operable by energy produced by the changing of the pressure of the gas between said mains for supplying oil atomizing gas from the high pressure main at a pressure higher than that of said high pressure main to said atomizer to atomize the oil in said atomizer.

7. The method of lubricating a gas main distributing system having a high pressure main and a low pressure main fed thereby comprising, withdrawing gas from the high pressure main, increasing the pressure of a portion of the gas by the expansion of a remaining greater portion of the withdrawn gas, atomizing oil by the pressure of gas portion so increased in pressure and entraining the atomized oil therewith, and supplying the oil-bearing gas to the low pressure main.

8. The method of lubricating a gas main distributing system having a high pressure main and a low pressure main which comprises, passing gas from the high pressure main to the low pressure main and reducing the pressure for the low pressure main, withdrawing a portion of the gas from. the high pressure main before it passes to the low pressure main and is reduced in pressure, lowering the pressure thereof outside the mains and introducing the gas so lowered in pressure into the low pressure main, increasing the pressure of another more limited portion of high pressure gas withdrawn as aforesaid with the energy resulting from the lowering in pressure of the first mentioned portion of gas, atomizing oil with the pressure of the more limited portion of gas under its increased pressure, and supplying the atomized oil and the gas therefor to the low pressure gas main.

9. In a gas distributing system, a low pressure main, a high pressure main, pressure reducing means connecting said mains, an oil atomizer, a gas compressor, means for conducting compressed gas therefrom to the atomizer to atomize the oil therein, means for conducting atomized oil to the low pressure main, a. gas pressure driven motor for driving said compressor, conduit means for bleeding a portion of the gas from the high pressure side of the pressure reducing means to the motor to drive the same and for conducting the exhaust gas under reduced pressure into the low pressure main, and conduit means for bleeding a more limited volume of gas from the high pressure side of the pressure reducing means to the compressor for compression therein, the compressor being of less volumetric capacity than the motor.

I-ERBERT D. STRAIGHT. 

